A disadvantage of traveling by airline, train, or motor vehicle is the inability to stabilize the head while sleeping in an upright or near upright position, which often results in a lack of sleep while traveling. Complaints about sleep deprivation due to discomfort are particularly common among persons who must travel long distances in a confined seating space, whether by airplane, motor vehicle, train, etc.
Body position and seat comfort in particular play vital roles in the overall traveling experience, since a passenger normally spends most of the duration of travel in a seat. The transportation industry, especially the common carrier airlines, are under tremendous economic pressure to increase revenue by adding more seats to their aircraft fleet to transport more passengers without increase in the overall size of the aircraft to accommodate these additional seats. The result has been less room between seats, which translates to a reduction in how far seats can be reclined without encroaching on the personal space of the persons sitting behind. In addition, the angle of recline is also limited by the viewing angle restrictions for multimedia entertainment systems which are now prominently located in the rear of most seat headrests for servicing the passenger sitting behind. In such a limited seat recline-angle, the force of gravity against the body, head, and arms is not as neutralized as it is when the body is in the fully-reclined sleeping position.
When a person is trying to sleep in a seated body position, the downward pull of gravity and other forces action on an individual's head must be opposed by some other force, such as a person's neck and shoulders and associated muscles. The neck and shoulders may not reliably maintain such a state of equilibrium of forces when a person is sleeping, which may cause a person's head to jolt when the body attempts to sleep. Furthermore, a simple headrest such as those often found on the back of seat, while helpful in providing support to the back of the head, usually do not alone effectively equalize all the vector forces acting on the head in the direction from the side of a head facing toward a shoulder.
Several sleeping aids have attempted to provide comfort when a person is in a seated body position by equalizing the forces acting on the head. A common device used by travelers is the generally U-shaped neck pillow. However, such U-shaped pillow is usually not designed for use in seats that already provide special support to the back of the head. The U-shaped pillow primarily ensures that the user's head is cushioned on the sides, but still allows the user's head to droop forward. These neck pillow cushions also fail to include a mechanism for providing a user with somewhere to put his or her arms, and user's arms dangle loosely due to the force of gravity. When a person is in a seated position, loose arms that do not have proper assistance for opposing the downward pull of gravity may lead to discomfort and make a sleeping state more difficult to achieve.